Bottom Line:
MAPIA strips were prepared employing 12 recombinant proteins.Antibody reactivity to these antigens was compared using a panel of sera collected from clinically asymptomatic (n = 16) and symptomatic (n = 41) culture-positive animals.We conclude that MAPIA is an effective screening tool to rapidly select multiple antigens of diagnostic utility to be used in a more sensitive point of care diagnostic test such as the Dual-Path Platform (DPP) multiplex test for the rapid detection of infected dogs.

Background: Domestic dogs are the principal reservoir hosts of Leishmania infantum in regions where visceral leishmaniasis (VL) is endemic. Although serologic methods are frequently used for the screening of infected dogs, antibody-based tests require further assessment, due to lack of sensitivity and specificity. In this study, we employed a multi-antigen printing immunoassay (MAPIA) to compare the antibody responses to novel recombinant proteins of L. infantum with the potential for the detection of canine VL.

Findings: MAPIA strips were prepared employing 12 recombinant proteins. Antibody reactivity to these antigens was compared using a panel of sera collected from clinically asymptomatic (n = 16) and symptomatic (n = 41) culture-positive animals. Our findings showed that the canine immune response to antigen differs between dogs and depends on infection status. Using this screening assay, when five out of the 12 antigens were combined, an overall 81% detection rate of L. infantum-infected dogs was achieved.

Conclusions: We conclude that MAPIA is an effective screening tool to rapidly select multiple antigens of diagnostic utility to be used in a more sensitive point of care diagnostic test such as the Dual-Path Platform (DPP) multiplex test for the rapid detection of infected dogs.

Mentions:
All MAPIA procedures were optimized with regard to antigen concentrations and serum dilution (data not shown). A total of 138 sera from clinically symptomatic (n = 41) and asymptomatic (n = 16) L. infantum-infected dogs, healthy controls (n = 40) and animals harboring other infections (n = 40) were tested against the selected panel of 12 antigens. The results showed variable antigen recognition patterns among the evaluated serum samples, as indicated in Figure 1. As shown in Table 1, the individual sensitivities of the 12 recombinant proteins coated onto nitrocellulose membranes ranged from 4 to 58% for identifying parasite-positive dogs. Nonetheless, each of the antigens detected some positive sera that others missed. When the individual recombinant proteins were combined, the total sensitivity increased to 81% (Figure 2), revealing that the antigens complemented each other. The well-known heterogeneous humoral immune response that develops in L. infantum-infected dogs [24] likely involves multiple antigens that are differentially recognized by the serum of each animal depending on the state of disease [8]. Therefore, further research into the development of a more reliable rapid test based on the combination of multiple antigens in a DPP format should be pursued.Figure 1

Mentions:
All MAPIA procedures were optimized with regard to antigen concentrations and serum dilution (data not shown). A total of 138 sera from clinically symptomatic (n = 41) and asymptomatic (n = 16) L. infantum-infected dogs, healthy controls (n = 40) and animals harboring other infections (n = 40) were tested against the selected panel of 12 antigens. The results showed variable antigen recognition patterns among the evaluated serum samples, as indicated in Figure 1. As shown in Table 1, the individual sensitivities of the 12 recombinant proteins coated onto nitrocellulose membranes ranged from 4 to 58% for identifying parasite-positive dogs. Nonetheless, each of the antigens detected some positive sera that others missed. When the individual recombinant proteins were combined, the total sensitivity increased to 81% (Figure 2), revealing that the antigens complemented each other. The well-known heterogeneous humoral immune response that develops in L. infantum-infected dogs [24] likely involves multiple antigens that are differentially recognized by the serum of each animal depending on the state of disease [8]. Therefore, further research into the development of a more reliable rapid test based on the combination of multiple antigens in a DPP format should be pursued.Figure 1

Bottom Line:
MAPIA strips were prepared employing 12 recombinant proteins.Antibody reactivity to these antigens was compared using a panel of sera collected from clinically asymptomatic (n = 16) and symptomatic (n = 41) culture-positive animals.We conclude that MAPIA is an effective screening tool to rapidly select multiple antigens of diagnostic utility to be used in a more sensitive point of care diagnostic test such as the Dual-Path Platform (DPP) multiplex test for the rapid detection of infected dogs.

Background: Domestic dogs are the principal reservoir hosts of Leishmania infantum in regions where visceral leishmaniasis (VL) is endemic. Although serologic methods are frequently used for the screening of infected dogs, antibody-based tests require further assessment, due to lack of sensitivity and specificity. In this study, we employed a multi-antigen printing immunoassay (MAPIA) to compare the antibody responses to novel recombinant proteins of L. infantum with the potential for the detection of canine VL.

Findings: MAPIA strips were prepared employing 12 recombinant proteins. Antibody reactivity to these antigens was compared using a panel of sera collected from clinically asymptomatic (n = 16) and symptomatic (n = 41) culture-positive animals. Our findings showed that the canine immune response to antigen differs between dogs and depends on infection status. Using this screening assay, when five out of the 12 antigens were combined, an overall 81% detection rate of L. infantum-infected dogs was achieved.

Conclusions: We conclude that MAPIA is an effective screening tool to rapidly select multiple antigens of diagnostic utility to be used in a more sensitive point of care diagnostic test such as the Dual-Path Platform (DPP) multiplex test for the rapid detection of infected dogs.